BEARING RECLAIMATION

I would think Chrome would peel. There are ways of building it up, like they use on automotive cam lobes? Isn't there a clever sort of spraying /welding with molten metal process or have I been at the meths again?

Del

No you aren't on drugs, we do metal spray here in the shop but I feel that would be more prone to peeling. I am leaning toward hard surface weld in grind but really do not want to have to deal with warping and extra work and expense required. I was hoping a hard chroming process is out there. The ball diameters (which are easily replaced with off the shelf 52100 material) are 1-3/4" diameter.

What is the physical arrangement? If its an axial load you could just grind it and take up the difference with a spacer...
Hmmm I'm sure you know that anyway...sorry I'll go back to sleep work.

Maybe regrind and bigger balls? ... we'd all like bigger balls

Del

So far this appears the way we are leaning.

On big expensive bearings like your, refurbishment is an option. There are several companies that do this, here is one...

http://www.ahrinternational.com/bearing_repair_and_refurbishment.htm

Chrome that you usually see peeling off has been electroplated.

Spray welding is done to resurface many large parts so that they can be machined back to their original specs. How they would rebuild the surface would depend upon the amount of metal needed.

I have seen spray welding done to many pump shafts none came back because the chrome peeled off.

Yes, we have never had one of our shafts come back peeled after spraying. However with the contact of each individual roller being small and the pressure of the unit with rotation I am not sure that chroming will work. I was just wondering if anyone has tried chroming the races of bearings.

Hi,

how has this bearing failed?

Most often the layer beneath pittings is nearly defect to some depth equivalent to the depth of pitting.

So chroming would require extensive high quality grinding. Else there will be early failure.

If grinding then as suggested above take new bigger balls (grade?) , thats best!

If the bearing is only corroded to a small depth (few micrometer) without any overload then slight grinding, plating and more grinding on hard-chrome will be possible but usually too costly, so why?

One reason to stay with plating may be corrosion resistance.

What is moved on this bearing? How are the radial axial and tilt errors specifications?

RHABE

Very large tol. about .078" tilt. The pitting (.001-.004") is caused by acidic corrosion. I think oversizing balls and close grinding going to best bet. The balls will be of 52100.

Hi,

why acidic corrosion?

Can this condition be changed or do you need a different type of bearing?

This momentary situation seems pretty costly.

RHABE

If it is still in operation, we have done great refurbishings of bearings and gears with Rewitec surface treatment that is applied in operation and provides a hard layer of ~10µ that does not peel off. www.rewitec.com

QUOTE The Rewitec surface treatment produces a uniformly graded layer, not a coating. Unlike a coating, the graded layer lacks an abrupt transition boundary and thereby resists cracking and spalling caused by thermal stress, physical stress, and even corrosion. UNQUOTE

It is also guaranteed for 1 year!

Resurfacing depends on failure reason, forget coatings as the surface wave produced in front of the balls will cause coatings to fail in a short time, layers offer a solution but it becomes a question of cost against future downtime and maintenance schedules. Is the resurfaced bearing going to last long enough to avoid downtime and last until its replacement date in your schedule?

This gives some info on causes of bearing failure it may help decide if going with resurfacing is the answer.

http://www.tortoiselogic.com/NSK/PDF/E7005a_Bearing%20Doctor.pdf

Can you change to rollers to spread the load?

SOLARBUSTER WROTE: layers offer a solution but it becomes a question of cost against future downtime and maintenance schedules.

OTTO34 COMMENT: Rewitec high silicon alloy layers cause no downtime since it is applied in operation using frictional force and load to difuse onto the damaged metal surface.

;-)

Hi,

post 9 says that pitting is 0.001 to 0.004" deep.

This is much too much for renewal by any method, this is deep destruction!

Do you have any experience with the stuff from Rewitec?, sounds interesting, I had a look at the website but there is little more than advertising.

RHABE